Light emitting device and led display apparatus including the same

ABSTRACT

A display apparatus includes a display substrate, and light emitting devices arranged on an upper surface of the display substrate. At least one of the light emitting devices includes a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack, and a third LED unit including a third light emitting stack. The second LED unit is disposed between the first LED unit and the third LED unit. Each of the first to third light emitting stacks includes a first conductivity type semiconductor layer and a second conductivity type semiconductor layer. The first conductivity type semiconductor layer and the second conductivity type semiconductor layer in each of the first to third light emitting stacks are stacked in a horizontal direction with respect to the upper surface of the display substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

The present application is a Non-provisional Application which claims the benefit of and priority to Provisional Application Nos. 63/008,126, filed on Apr. 10, 2020, and 62/956,966, filed on Jan. 3, 2020, the disclosures of which are incorporated herein by their entirety.

TECHNICAL FIELD

Exemplary embodiments of the present disclosure relate to a light emitting device and an LED display apparatus including the same.

BACKGROUND ART

A light emitting diode (LED) is an inorganic light source and is used in various fields, such as a display apparatus, a vehicular lamp, general lighting, and the like. With various advantages including long lifespan, low power consumption, and rapid response, light emitting diodes have rapidly replaced existing light sources.

A typical light emitting diode is generally used as a backlight source in a display apparatus. In recent years, an LED display adapted to realize a direct image using light emitting diodes is available. Such an LED display is referred to as a micro-LED display or a mini-LED display depending upon the size of light emitting devices.

In general, a display apparatus realizes various colors using a mixture of blue light, green light and red light. The display apparatus includes multiple pixels in order to realize various images, in which each of the pixels includes blue, green and red subpixels, a color of a certain pixel is determined through combination of colors of these subpixels, and an image is realized through combination of these pixels.

Since an LED emits light of various colors depending upon materials thereof, the display apparatus may be manufactured by arranging individual light emitting devices configured to emit blue light, green light and red light in a two-dimensional plane. However, arrangement of one light emitting device on each subpixel increases the number of light emitting devices, thereby causing increase in time consumption in a mounting process.

Summary Exemplary embodiments of the present disclosure provide a light emitting device having a novel structure suitable for an LED display apparatus and an LED display apparatus including the same.

Exemplary embodiments of the present disclosure provide an LED display apparatus allowing change of a stacking sequence of LEDs without being restricted by wavelengths of light emitted from the LEDs.

Exemplary embodiments of the present disclosure provide a light emitting device allowing formation of electrodes without affecting light emitting regions of LEDs, and an LED display apparatus including the same.

In some forms, the present disclosure provides a display apparatus including a display substrate, and light emitting devices arranged on an upper surface of the display substrate. At least one of the light emitting devices includes a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack, and a third LED unit including a third light emitting stack. The second LED unit is disposed between the first LED unit and the third LED unit. Each of the first to third light emitting stacks includes a first conductivity type semiconductor layer and a second conductivity type semiconductor layer. The first conductivity type semiconductor layer and the second conductivity type semiconductor layer in each of the first to third light emitting stacks are stacked in a horizontal direction with respect to the upper surface of the display substrate.

In other forms, the present disclosure provides a display apparatus including a display substrate and light emitting devices arranged on an upper surface of the display substrate. At least one of the light emitting devices includes a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack, a third LED unit including a third light emitting stack, a first bonding layer coupling the first LED unit to the second LED unit, and a second bonding layer coupling the second LED unit to the third LED unit. The first to third LED units are coupled to one another in a horizontal direction with respect to the upper surface of the display substrate.

In another form, the present disclosure provides a light emitting device including a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack, and a third LED unit including a third light emitting stack. The light emitting device further includes a first bonding layer coupling the first LED unit to the second LED unit, a second bonding layer coupling the second LED unit to the third LED unit, a first electrode electrically connected to the first LED unit, a second electrode electrically connected to the second LED unit, a third electrode electrically connected to the third LED unit, and a common electrode electrically connected to the first to third LED units. The second electrode is electrically connected to the second LED unit on one side surface of the second LED unit.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view of an LED display apparatus according to one or more exemplary embodiments of the present disclosure.

FIG. 2 is a schematic cross-sectional view taken along line A-A′ of FIG. 1.

FIG. 3 is a schematic perspective view of a light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 4 is a schematic sectional view of a light emitting stack structure for manufacturing a light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 5 is a schematic sectional view of another light emitting stack structure for manufacturing a light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 6 is a schematic sectional view of yet another light emitting stack structure for manufacturing a light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 7 is a schematic sectional view of further another light emitting stack structure for manufacturing a light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 8 is a schematic perspective view of another light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 9 is a schematic perspective view of yet another light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 10 is a schematic perspective view of further another light emitting device module according to one or more exemplary embodiments of the present disclosure.

FIG. 11 is a schematic perspective view of another LED display apparatus according to one or more exemplary embodiments of the present disclosure.

FIG. 12 is a schematic perspective view of another LED display apparatus according to one or more exemplary embodiments of the present disclosure.

FIG. 13 is a schematic perspective view of further another LED display apparatus according to one or more exemplary embodiments of the present disclosure.

FIG. 14 is a schematic perspective view of a light emitting device module according to one or more exemplary embodiments of the present disclosure.

FIG. 15 is a schematic sectional view of a light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 16 is a schematic sectional view of another light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 17 is a schematic sectional view of yet another light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 18 is a schematic perspective view of another light emitting device according to one or more exemplary embodiments of the present disclosure.

FIG. 19 is a schematic perspective view of further another light emitting device module according to one or more exemplary embodiments of the present disclosure.

FIG. 20 is a schematic perspective view of yet another LED display apparatus according to one or more exemplary embodiments of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so as to fully convey the spirit of the present disclosure to those skilled in the art. Accordingly, the present disclosure is not limited to the embodiments disclosed herein and can also be implemented in different forms. In the drawings, widths, lengths, thicknesses, and the like of elements can be exaggerated for clarity and descriptive purposes. When an element or component is referred to as being “disposed above” or “disposed on” another element or component, it can be directly “disposed above” or “disposed on” the other element or component or intervening elements or components can be present. Throughout the specification, like reference numerals denote like elements having the same or similar functions.

In order to reduce time consumption in the mounting process, a stack type light emitting device has been studied. For example, light of red, blue and green colors may be realized using a light emitting device manufactured by stacking a red LED, a blue LED and a green LED. As a result, it is possible to provide one pixel capable of emitting red, blue and green colors through one light emitting device, thereby enabling reduction in the number of light emitting devices mounted in the display apparatus to ⅓ of the number of light emitting devices used in the related art.

However, in a typical stack type light emitting device, light emitted from an LED disposed at a lower side thereof is discharged after passing through LEDs disposed on the LED at the lower side. Accordingly, there is a need for restriction of the stacking sequence of the LEDs in consideration of light absorption. Moreover, light emitting regions of the LEDs stacked one above another are affected by electrodes connected to each of the LEDs.

In some forms, exemplary embodiments of the present disclosure provide a display apparatus. The display apparatus includes a display substrate, and light emitting devices arranged on an upper surface of the display substrate. At least one of the light emitting devices includes a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack, and a third LED unit including a third light emitting stack. The second LED unit is disposed between the first LED unit and the third LED unit. Each of the first to third light emitting stacks includes a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, and the first conductivity type semiconductor layer and the second conductivity type semiconductor layer in each of the first to third light emitting stacks are stacked in a horizontal direction with respect to the upper surface of the display substrate.

Since the semiconductor layers are stacked in the horizontal direction with respect to the upper surface of the display substrate, light emitted from the semiconductor layers may be discharged without passing through other light emitting stacks. As a result, the stacking sequence of the first to third light emitting stacks is not restricted by the wavelength of light emitted therefrom.

Each of the first to third light emitting stacks may further include an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer.

In at least one variant, one of the first to third LED units may emit red light, another LED unit may emit green light, and the remaining LED unit may emit blue light.

In another variant, the second LED unit may emit red light. In a typical stack structure, since blue light or green light is absorbed by a light emitting stack adapted to emit red light, a second LED unit emitting red light is not disposed between the first LED unit and the third LED unit, which emit light having a shorter wavelength than the light emitted from the second LED unit. However, according to this embodiment, since the light emitted from the second LED unit may be discharged without passing through the first LED unit and the third LED unit, the second LED unit may be configured to emit red light.

In yet another variant, the at least one light emitting device may further include a substrate disposed at a side of the third LED unit. The at least one light emitting device may further include a substrate disposed at a side of the first LED unit.

In yet another variant, the light emitting devices may be spaced apart from one another by a black material. Accordingly, contrast ratios of the light emitting devices can be improved.

In another variant, the display apparatus may include multiple light emitting device modules arranged parallel to one another on the display substrate. Each of the light emitting device modules includes multiple light emitting devices coupled to one another in a direction in which the first conductivity type semiconductor layer and the second conductivity type semiconductor layer are stacked.

The light emitting devices in each of the light emitting device modules may include a substrate of a black material. Further, the display apparatus may further include a black material disposed in a region between the light emitting device modules.

The at least one light emitting device may further include a first electrode electrically connected to the first LED unit, a second electrode electrically connected to the second LED unit, a third electrode electrically connected to the third LED unit, and a common electrode electrically connected to the first to third LED units.

The first to third LED electrodes and the common electrode may be disposed between the at least one light emitting device and the display substrate.

The display apparatus may further include a carrier substrate disposed between the display substrate and the at least one light emitting device, wherein the carrier substrate may include connectors electrically connecting the first to third electrodes and the common electrode to connection pads of the display substrate.

In other forms, exemplary embodiments of the present disclosure provide a display apparatus. The display apparatus includes a display substrate, and light emitting devices arranged on an upper surface of the display substrate. At least one of the light emitting devices includes a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack, a third LED unit including a third light emitting stack. One of the light emitting devices further includes a first bonding layer coupling the first LED unit to the second LED unit, and a second bonding layer coupling the second LED unit to the third LED unit. The first to third LED units are coupled to one another in a horizontal direction with respect to the upper surface of the display substrate.

Accordingly, light emitted from the first to third LED units may be discharged without passing through other LED units.

In one variant the second LED unit may emit red light.

In another form, exemplary embodiments of the present disclosure provide a light emitting device. The light emitting device includes a first LED unit including a first light emitting stack, a second LED unit including a second light emitting stack and a third LED unit including a third light emitting stack. The light emitting device further includes a first bonding layer coupling the first LED unit to the second LED unit, a second bonding layer coupling the second LED unit to the third LED unit, a first electrode electrically connected to the first LED unit, a second electrode electrically connected to the second LED unit, a third electrode electrically connected to the third LED unit, and a common electrode electrically connected to the first to third LED units. The second electrode is electrically connected to the second LED unit on a side surface of the second LED unit.

As the second electrode is disposed on the side surface of the second LED unit, the light emitting device may be mounted on the display substrate such that the first to third LED units can be arranged in the horizontal direction with respect to the upper surface of the display substrate.

Furthermore, the first electrode, the second electrode, the third electrode, and the common electrode may be disposed on the same side surface of the light emitting device.

In at least one variant, the light emitting device may further include a first substrate coupled to the first LED unit and a second substrate coupled to the second LED unit. The first substrate and the second substrate include through-holes, and one of the first electrode and the common electrode may be electrically connected to the first LED unit through the through-hole of the first substrate. One of the third electrode and the common electrode may be electrically connected to the third LED unit through the through-hole of the second substrate.

The light emitting device may further include a substrate disposed at a side of the third LED unit. A portion of the third electrode may be disposed on a side surface of the substrate.

In another variant, the first LED unit may further include a first reflective layer disposed on the first light emitting stack, the second LED unit may further include a second reflective layer disposed on the second light emitting stack, and the third LED unit may further include a third reflective layer and a fourth reflective layer disposed at opposite sides of the third light emitting stack.

In further another variant, the light emitting device may further include a first ohmic electrode interposed between the first light emitting stack and the first reflective layer, a second ohmic electrode interposed between the second light emitting stack and the second reflective layer, and a third ohmic electrode interposed between the third light emitting stack and the third reflective layer.

In yet another variant, the first LED unit may further include a first contact electrode forming ohmic contact with the first light emitting stack, the second LED unit may further include a second contact electrode forming ohmic contact with the second light emitting stack, and the third LED unit may further include a third contact electrode forming ohmic contact with the third light emitting stack. Furthermore, at least one of the first to third light emitting stacks or at least one of the first to third contact electrodes may have roughness.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic plan view of an LED display apparatus 1000 according to one or more exemplary embodiments of the present disclosure, FIG. 2 is a schematic cross-sectional view taken along line A-A′ of FIG. 1, and FIG. 3 is a schematic perspective view of a light emitting device according to one or more exemplary embodiments of the present disclosure.

Referring to FIG. 1, FIG. 2, and FIG. 3, the LED display apparatus 1000 includes a display substrate 101, and multiple light emitting devices 100. The LED display apparatus 1000 may be so-called a micro-LED display apparatus, in which one subpixel has a light emitting area of 10,000 μm² or less, specifically 4,000 μm² or less, more specifically 1,000 μm² or less.

The display substrate 101 may include circuits connected to the light emitting devices 100. As shown in FIG. 2, connection pads 103 may be exposed on the display substrate 101 and the light emitting devices 100 may be connected to the connection pads 103.

The light emitting devices 100 may be aligned on the display substrate 101. As shown in FIG. 1, the light emitting devices 100 may be aligned in a matrix on the display substrate 101 and each of the light emitting devices 100 may constitute one pixel.

The light emitting device 100 may include a first LED unit LEU1, a second LED unit LEU2, a third LED unit LEU3, and bonding layers 61, 63, as shown in FIG. 2. In addition, as shown in FIG. 3, the light emitting device 100 may include first to third electrodes 20 e, 30 e, 40 e and a common electrode 50 e.

The first LED unit LEU1 may emit a first color of light, the second LED unit LEU2 may emit a second color of light, and the third LED unit LEU3 may emit a third color of light. The first to third colors of light may be red light, green light and blue light, respectively, without being limited thereto. Alternatively, the first color of light may be green light, the second color of light may be red light, and the third color of light may be blue light. In a typical stack type light emitting device, the stacking sequence is restricted by the wavelength of light emitted from the light emitting device, whereas the wavelength of light emitted from the light emitting device according to this embodiment does not restrict the stacking sequence of the LED units LEU1, LEU2, LEU3. For convenience of description, unless stated otherwise, the first LED unit LEU1, the second LED unit LEU2, and the third LED unit LEU3 will be described as emitting red light, green light, and blue light, respectively.

Each of the first to third LED units LEU1, LEU2, LEU3 may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer. These layers are disposed perpendicular to an upper surface of the display substrate 101. That is, in the typical stack type light emitting device, the semiconductor layers are stacked in a perpendicular direction (z-direction) corresponding to a direction in which light is emitted from an upper surface of display substrate, whereas, in the light emitting device according to this embodiment, the semiconductor layers are stacked in a horizontal direction (x-direction) with respect to the upper surface of the display substrate. The light is emitted in the z-direction and the x-direction is generally perpendicular to the z-direction. The first conductivity type semiconductor layer, the active layer, and the second conductivity type semiconductor layer will be described below in detail with reference to FIG. 4.

The first bonding layer 61 is disposed between the first LED unit LEU1 and the second LED unit LEU2 to couple the first LED unit LEU1 to the second LED unit LEU2. The second bonding layer 63 is disposed between the second LED unit LEU2 and the third LED unit LEU3 to couple the second LED unit LEU2 to the third LED unit LEU3. That is, the first, second and third LED units LEU1, LEU2, LEU3 are coupled to one another, side by side, by the first and second bonding layers 61, 63 to constitute one light emitting device 100. The one light emitting device 100 includes the first to third LED units LEU1, LEU2, LEU3 to emit at least first to third colors of light, thereby providing one pixel.

The first and second bonding layers 61, 63 may include a non-conductive material that transmits light emitted from the first and second bonding layers 61, 63. The first and second bonding layers 61, 63 may include an optically clear adhesive (OCA), for example, an epoxy, a polyimide resin, SUB, spin-on-glass (SOG), and benzocyclobutene (BCB), without being limited thereto. In addition, according to this embodiment, since the first and second bonding layers 61, 63 are not required to allow light generated from the first to third LED units LEU1, LEU2, LEU3 to pass therethrough, the first and second bonding layers 61, 63 may be formed of an opaque material. For example, the first and second bonding layers 61, 63 may include a light absorption material or a light reflection material.

The first electrode 20 e, the second electrode 30 e, the third electrode 40 e, and the common electrode 50 e may be formed to allow independent operation of the first to third LED units LEU1, LEU2, LEU3. In one embodiment, the first electrode 20 e may be electrically connected to an anode of the first LED unit LEU1, the second electrode 30 e may be electrically connected to an anode of the second LED unit LEU2, and the third electrode 40 e may be electrically connected to an anode of the third LED unit LEU3. The common electrode 50 e may be commonly electrically connected to cathodes of the first, second and third LED units LEU1, LEU2, LEU3. In another embodiment, the first to third electrodes 20 e, 30 e, 40 e may be electrically connected to cathodes of the first to third LED units LEU1, LEU2, LEU3, respectively, and the common electrode 50 e may be commonly electrically connected to anodes of the first, second, and third LED units LEU1, LEU2, LEU3.

As shown in FIG. 3, the first electrode 20 e may be electrically connected to the first LED unit LEU1 at one side of the first LED unit LEU1. The second electrode 30 e may be electrically connected to the second LED unit LEU2 at one side of the second LED unit LEU2 and the third electrode 40 e may be electrically connected to the third LED unit LEU3 at one side of the third LED unit LEU3. On the other hand, the common electrode 50 e may be disposed over side surfaces of the first to third LED units LEU1, LEU2, LEU3 and may be electrically connected thereto. In order to increase the area of the first electrode 20 e, a portion of the first electrode 20 e may be disposed on the first bonding layer 61. In order to increase the area of the second electrode 30 e, a portion of the second electrode 30 e may be disposed on the second bonding layer 63.

The electrodes 20 e, 30 e, 40 e, 50 e are not limited to a particular shape and may have various shapes, for example, a rectangular shape, a circular shape, or a polygonal shape. In addition, before formation of the electrodes 20 e, 30 e, 40 e, 50 e, an insulating layer may be formed to partially expose the first to third LED units LEU1, LEU2, LEU3. The electrodes 20 e, 30 e, 40 e, 50 e may be electrically connected to the exposed portion of the first to third LED units LEU1, LEU2, LEU3 through the insulating layer.

The first, second and third electrodes 20 e, 30 e, 40 e and the common electrode 50 e may be bonded to the connection pads 103 on the display substrate 101 as shown in FIG. 2. Accordingly, the first, second and third electrodes 20 e, 30 e, 40 e and the common electrode 50 e may be disposed between the light emitting device 100 and the display substrate 101, and the first to third LED units LEU1, LEU2, LEU3 may emit light upwards through surfaces thereof opposite to the first to third electrodes 20 e, 30 e, 40 e.

According to this embodiment, the first LED unit LEU1, the second LED unit LEU2, and the third LED unit LEU3 are coupled to one another, side by side, in the horizontal direction on the upper surface of the display substrate 101. Accordingly, since light emitted from each of the first to third LED units LEU1, LEU2, LEU3 does not interfere with light emitted from the other LED units, the stacking sequence of these LED units may be changed as needed. Furthermore, the first to third LED units LEU1, LEU2, LEU3 closely contact with one another, thereby enabling easy mixing of the colors of light emitted therefrom and free adjustment of the size of the pixel through minimization of the area of the display substrate 101 occupied by the light emitting device 100.

The light emitting device 100 may be provided from a light emitting stack structure formed by stacking the first to third LED units LEU1, LEU2, LEU3. Hereinafter, various light emitting stack structures will be described with reference to FIG. 4 to FIG. 7.

FIG. 4 is a schematic sectional view of a light emitting stack structure for manufacturing a light emitting device according to one exemplary embodiment of the present disclosure.

Referring to FIG. 4, the light emitting stack structure according to the exemplary embodiment includes a substrate 11, a first light emitting stack 20, a second light emitting stack 30, and a third light emitting stack 40. The first light emitting stack 20 includes a first conductivity type semiconductor layer 21, an active layer 23, and a second conductivity type semiconductor layer 25; the second light emitting stack 30 includes a first conductivity type semiconductor layer 31, an active layer 33, and a second conductivity type semiconductor layer 35; and the third light emitting stack 40 includes a first conductivity type semiconductor layer 41, an active layer 43, and a second conductivity type semiconductor layer 45. Further, contact electrodes 25 p, 35 p, 45 p may be disposed on the second conductivity type semiconductor layers 25, 35, 45 of the light emitting stacks 20, 30, 40, respectively.

The substrate 11 may be a growth substrate, for example, a sapphire substrate, which allows epitaxial growth of the third light emitting stack 40 thereon. It should be understood that the substrate 11 is not limited to the sapphire substrate and may include various other transparent insulating materials. For example, the substrate 11 may include glass, quartz, silicon, organic polymers or an organic-inorganic composite material, for example, silicon carbide (SiC), gallium nitride (GaN), indium gallium nitride (InGaN), aluminum gallium nitride (AlGaN), aluminum nitride (AlN), gallium oxide (Ga₂O₃), or a silicon substrate. In addition, the substrate 11 may include roughness formed on an upper surface thereof and may be, for example, a patterned sapphire substrate. The third light emitting stack 40 may have roughness on a lower surface thereof, which adjoins the substrate 11 having roughness formed on the upper surface thereof, thereby improving efficiency in extraction of light generated in the third light emitting stack 40. The substrate 11 may be removed in the course of manufacturing the light emitting device 100, without being limited thereto. Alternatively, the substrate may remain thereon.

The first light emitting stack 20 may include semiconductor materials, such as AlGaAs, GaAsP, AlGaInP, and GaP, which emit red light, without being limited thereto.

According to one embodiment, the second light emitting stack 30 may include a semiconductor material, such as GaN, InGaN, GaP, AlGaInP, AlGaP, and the like, which emit green light, without being limited thereto. The second contact electrode 35 p is disposed on the second conductivity type semiconductor layer 35 of the second light emitting stack 30.

According to one embodiment, the third light emitting stack 40 may include a semiconductor material, such as GaN, InGaN, ZnSe, and the like, which emit blue light, without being limited thereto. The third contact electrode 45 p is disposed on the second conductivity type semiconductor layer 45 of the third light emitting stack 40 as shown in FIG. 4.

Each of the first conductivity type semiconductor layers 21, 31, 41 and the second conductivity type semiconductor layers 25, 35, 45 of the first, second and third light emitting stacks 20, 30, 40 may have a single layer or multilayer structure. In some embodiments, each of the first and second conductivity type semiconductor layers may include a super-lattice layer. Furthermore, the active layers 23, 33, 43 of the first, second and third light emitting stacks 20, 30, 40 may have a single layer or multilayer structure.

The first conductivity type semiconductor layers 21, 31, 41 of each of the light emitting stacks may be n-type semiconductor layers and the second conductivity type semiconductor layers 25, 35, 45 may be p-type semiconductor layers. In this case, the third light emitting stack 40 may have an opposite stacking sequence to the first light emitting stack 20 and the second light emitting stack 30. As a result, the p-type semiconductor layer 45 may be disposed on the active layer 43, thereby simplifying a manufacturing process. Furthermore, the n-type semiconductor layer and the p-type semiconductor layer may be interchanged.

The first, second and third contact electrodes 25 p, 35 p, 45 p may be formed of any materials capable of forming ohmic contact with the second conductivity type semiconductor layers 25, 35, 45, without limitation. Each of the first, second and third contact electrodes 25 p, 35 p, 45 p may include a transparent conductive material that transmits light, without being limited thereto. For example, the contact electrodes 25 p, 35 p, 45 p may include a transparent conductive oxide (TCO), for example, SnO, InO2, ZnO, ITO, ITZO, and the like.

The first bonding layer 61 is disposed between the first light emitting stack 20 and the second light emitting stack 30, and the second bonding layer 63 is disposed between the second light emitting stack 30 and the third light emitting stack 40. Since materials of the first and second bonding layers 61, 63 are similar to the materials described above, detailed description thereof will be omitted.

In the third light emitting stack 40, the first conductivity type semiconductor layer 41, the active layer 43 and the second conductivity type semiconductor layer 45 may be sequentially grown on the substrate 11 by, for example, metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE). The third contact electrode 45 p may be formed on the second conductivity type semiconductor layer 45 by, for example, physical vapor deposition or chemical vapor deposition, and may include a transparent conductive oxide (TCO), for example, SnO, InO₂, ZnO, ITO, ITZO, and the like, or an ohmic metal layer.

For the third light emitting stack 40 emitting blue light, the substrate 11 includes Al₂O₃ (for example: a sapphire substrate) and the third contact electrode 45 p may include Ni/Au or a transparent conductive oxide (TCO), such as SnO, InO₂, ZnO, ITO, ITZO and the like. Each of the first and second light emitting stacks 20, 30 may be similarly formed by sequentially growing a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer on a temporary substrate. The contact electrode may be formed on each of the second conductivity type semiconductor layers by, for example, plating, physical vapor deposition, or chemical vapor deposition.

In one embodiment, the first light emitting stack 20 may be attached to the second light emitting stack 30 through the first bonding layer 61 and the second light emitting stack 30 may be attached to the third light emitting stack 40 through the second bonding layer 63. For example, after the third light emitting stack 40 is grown on the substrate 11, the second light emitting stack 30 grown on the temporary substrate may be attached to the third light emitting stack 40 through the second bonding layer 63. Thereafter, the temporary substrate is removed from the second light emitting stack 30. Next, the first light emitting stack 20 grown on another temporary substrate may be attached to the second light emitting stack 30 through the first bonding layer 61. Thereafter, the temporary substrate is removed from the first light emitting stack 20.

In another embodiment, the first and second light emitting stacks 20, 30 may be coupled to each other via the first bonding layer 61 interposed therebetween, and at least one of the temporary substrates of the first and second light emitting stacks 20, 30 may be removed by a laser lift-off process, a chemical process, a mechanical process, and the like. In addition, the first and second light emitting stacks 20, 30 may be coupled to the third light emitting stack 40 via the second bonding layer 63 interposed therebetween, and the remaining temporary substrate of the first and second light emitting stacks 20, 30 may be removed by a laser lift-off process, a chemical process, a mechanical process, and the like.

The light emitting device 100 as shown in FIG. 3 may be realized by patterning the light emitting stack structure according to this embodiment and forming the first to third electrodes 20 e, 30 e, 40 e and the common electrode 50 e on the side surfaces of the first to third light emitting stacks 20, 30, 40. The first LED unit LEU1 described above includes the first light emitting stack 20 and the first contact electrode 25 p; the second LED unit LEU2 includes the second light emitting stack 30 and the second contact electrode 35 p; and the third LED unit LEU3 includes the third light emitting stack 40 and the third contact electrode 45 p.

Such light emitting devices 100 are arranged individually or as a group on the display substrate 101, thereby realizing the display apparatus 1000. The first to third electrodes 20 e, 30 e, 40 e and the common electrode 50 e formed on the light emitting device 100 may be bonded to the connection pads 103 on the display substrate 101.

In this embodiment, the light emitting stack structure includes three light emitting stacks 20, 30, 40. However, it should be understood that the present disclosure is not limited to a particular number of light emitting stacks. For example, in some embodiments, the light emitting stack structure may include two or more light emitting stacks. As such, the light emitting device 100 may include three light emitting stacks 20, 30, 40, without being limited thereto. Alternatively, the light emitting device 100 may include two light emitting stacks or four or more light emitting stacks.

FIG. 5 is a schematic sectional view of a light emitting stack structure for manufacturing a light emitting device according to one exemplary embodiment of the present disclosure.

Referring to FIG. 5, the light emitting stack structure according to this embodiment is generally similar to the light emitting stack structure described with reference to FIG. 4 except that a third bonding layer 65 is interposed between the substrate 11 and the third light emitting stack 40.

According to this embodiment, the substrate 11 is a support substrate for supporting the first to third light emitting stacks 20, 30, 40 and is not necessarily a growth substrate for growth of the third light emitting stack 40. The substrate 11 may be a sapphire substrate, without being limited thereto. Alternatively, the substrate 11 may include a black material capable of absorbing light, for example, a black epoxy or black silicone, or a light reflective material, for example, a white epoxy. The substrate 11 may be directly coupled to the third light emitting stack 40 or may be coupled thereto by the third bonding layer 65. The substrate 11 may be separated from the third light emitting stack 40 to provide the light emitting device 100, without being limited thereto. Alternatively, the substrate 11 may remain in a state of being attached to the third light emitting stack 40.

FIG. 6 is a schematic sectional view of a light emitting stack structure for manufacturing a light emitting device according to another exemplary embodiment of the present disclosure.

Referring to FIG. 6, the light emitting stack structure according to this embodiment is generally similar to the light emitting stack structure described with reference to FIG. 5 except that the first conductivity type semiconductor layer 41 of the third light emitting stack 40 is substituted with the second conductivity type semiconductor layer 45 and the third contact electrode 45 p is interposed between the third bonding layer 65 and the second conductivity type semiconductor layer 45.

FIG. 7 is a schematic sectional view of a light emitting stack structure for manufacturing a light emitting device according to further another exemplary embodiment of the present disclosure.

Referring to FIG. 7, the light emitting stack structure according to this embodiment is generally similar to the light emitting stack structure described with reference to FIG. 4 except that substrates 11 a, 11 b are disposed at opposite sides of the first to third light emitting stack structures 20, 30, 40.

The substrate 11 a may be a growth substrate for growth of the third light emitting stack 40, without being limited thereto. In addition, as described with reference to FIG. 5 or FIG. 6, the substrate 11 a may be attached to the third light emitting stack 40 through the third bonding layer 65 or may be directly attached thereto without the third bonding layer 65.

The substrate 11 b may be a growth substrate for growth of the first light emitting stack 20, without being limited thereto. The substrate 11 b may be attached to the first light emitting stack 20 through a bonding layer or may be directly attached thereto. The sequence of the first to third light emitting stacks 20, 30, 40 interposed between the substrate 11 a and the substrate 11 b is not particularly limited.

In one embodiment, the substrate 11 b may be a growth substrate for growth of the first light emitting stack 20; the first light emitting stack 20 may emit green light; the second light emitting stack 30 may emit red light; and the third light emitting stack 40 may emit blue light. In this embodiment, both the substrate 11 a and the substrate 11 b may be sapphire substrates. In another embodiment, the substrate 11 a and the substrate 11 b may include a black material capable of absorbing light, for example, a black epoxy or black silicone.

FIG. 8 is a schematic perspective view of a light emitting device 100 a according to another exemplary embodiment of the present disclosure.

Referring to FIG. 8, the light emitting device 100 a is generally similar to the light emitting device 100 and further includes the substrate 11. That is, the light emitting device 100 a may be manufactured by dividing the light emitting stacks 20, 30, 40 without removing the substrate 11 from the light emitting stack structure of FIG. 4. According to this embodiment, a portion of the third electrode 40 e may be disposed on the substrate 11, thereby enabling formation of the third electrode 40 e.

FIG. 9 is a schematic perspective view of a light emitting device 100 b according to further another exemplary embodiment of the present disclosure.

Referring to FIG. 9, the light emitting device 100 b according to this embodiment may be manufactured by dividing the light emitting stacks 20, 30, 40 together with the substrates 11 a, 11 b without removing the substrates 11 a, 11 b from, for example, the light emitting stack structure of FIG. 7.

Here, the substrates 11 a, 11 b may be a transparent substrate, such as a sapphire substrate, without being limited thereto. Alternatively, the substrate 11 a, 11 b may include a black material capable of absorbing light, for example, a black epoxy or black silicone.

FIG. 10 is a schematic perspective view of a light emitting device module according to one exemplary embodiment of the present disclosure.

Referring to FIG. 10, the light emitting device module according to this embodiment includes multiple light emitting devices 100 b. The light emitting devices 100 b of FIG. 9 are coupled to each other in the stacking sequence of the first to third light emitting units LEU1, LEU2, LEU3. That is, the substrates 11 a, 11 b of adjacent light emitting devices 100 b may be coupled to each other.

At least two light emitting devices 100 b may be coupled to each other in the stacking direction, thereby providing a column-shaped light emitting device module. The light emitting device module may be mounted on the display substrate 101, thereby further facilitating a mounting process. For the substrates 11 a, 11 b formed of a black material, it is possible to prevent interference of light between the light emitting devices 100 b.

Although not shown in the drawings, an anti-reflection layer or an anti-scattering layer may be further formed on a light exit surface side of the light emitting device module. The anti-reflection layer or the anti-scattering layer may be formed of an organic material or an inorganic material of an oxide or a nitride, for example, SiO₂, SiN_(x), Al₂O₃, or an epoxy.

FIG. 11 is a schematic perspective view of an LED display apparatus according to one exemplary embodiment of the present disclosure.

Referring to FIG. 11, the LED display apparatus according to this embodiment is manufactured by mounting the light emitting device module of FIG. 10 on the display substrate 101.

The display apparatus may be realized by preparing light emitting device modules including the multiple light emitting devices in the longitudinal direction, followed by arranging the light emitting device modules on the display substrate 101.

FIG. 12 is a schematic perspective view of an LED display apparatus according to one exemplary embodiment of the present disclosure.

Referring to FIG. 12, the LED display apparatus according to this embodiment is generally similar to the LED display apparatus described with reference to FIG. 11 and further includes a light blocking material 110. The light blocking material 110 may cover both side surfaces of the column-shaped light emitting device module. For the LED display apparatus including multiple light emitting device modules, the light blocking material 110 fills a region between the light emitting device modules while covering outer side surfaces of the light emitting device modules.

The light blocking material 110 may be formed of, for example, a light absorption material, such as a black material, or a light reflective material, such as a white epoxy. As a result, it is possible to prevent interference of light between the light emitting device modules. The substrates 11 a, 11 b may be formed of a black material to prevent interference of light between the light emitting device modules, thereby improving contrast ratio between the pixels.

FIG. 13 is a schematic perspective view of an LED display apparatus according to one exemplary embodiment of the present disclosure.

Referring to FIG. 13, the LED display apparatus according to this embodiment is generally similar to the LED display apparatus described with reference to FIG. 12 and further includes a transparent layer 120 for reducing light scattering or light reflection, for example, an anti-scattering layer. The transparent layer 120 suppresses light interference between the pixels while reducing light scattering or light reflection.

FIG. 14 is a schematic perspective view of a light emitting device module according to one exemplary embodiment of the present disclosure.

Referring to FIG. 14, the light emitting device module according to this embodiment is generally similar to the light emitting device module described with reference to FIG. 10 except that the substrate 11 b is omitted in the region between the light emitting devices.

For example, the light emitting device module according to this embodiment may be realized by coupling the light emitting device 100 a described with reference to FIG. 8 and the light emitting device 100 b described with reference to FIG. 9.

According to this embodiment, the light emitting device module can further reduce a gap between the pixels, thereby achieving further reduction in distance between the light emitting devices.

FIG. 15 is a schematic sectional view of a light emitting device 100 c according to one exemplary embodiment of the present disclosure.

Referring to FIG. 15, the light emitting device 100 c according to this embodiment is generally similar to the light emitting device 100 described with reference to FIG. 1 to FIG. 3 and further includes reflective layers 21 r, 31 r, 41 r, 45 r.

The first LED unit LEU1 may include a first reflective layer 21 r together with the first light emitting stack 20 and the contact electrode 25P. The first reflective layer 21 r may be disposed at an opposite side of the contact electrode 25 p. As shown in FIG. 4, the contact electrode 25 p may form ohmic contact with the second conductivity type semiconductor layer 25 and the first reflective layer 21 r may be formed on the first conductivity type semiconductor layer 21. The first reflective layer 21 r may form ohmic contact with the first conductivity type semiconductor layer 21, without being limited thereto. That is, the first reflective layer 21 r may form Schottky contact with the first conductivity type semiconductor layer 21 or may be insulated from the first conductivity type semiconductor layer 21. The first reflective layer 21 r reflects light emitted from the first light emitting stack 20, thereby preventing light loss.

The second LED unit LEU2 may include a second reflective layer 31 r together with the second light emitting stack 30 and the contact electrode 35 p. The second reflective layer 31 r may be disposed at an opposite side of the contact electrode 35 p. As shown in FIG. 4, the contact electrode 35 p may form ohmic contact with the second conductivity type semiconductor layer 35 and the second reflective layer 31 r may be formed on the first conductivity type semiconductor layer 31. The first bonding layer 61 may couple the second reflective layer 31 r to the contact electrode 25 p. Further, the second reflective layer 31 r may form ohmic contact with the first conductivity type semiconductor layer 31, without being limited thereto. That is, the second reflective layer 31 r may form Schottky contact with the first conductivity type semiconductor layer 31 or may be insulated from the first conductivity type semiconductor layer 31. The second reflective layer 31 r may reflect light emitted from the second light emitting stack 30. Furthermore, the second reflective layer 31 r may reflect light emitted from the first light emitting stack 20.

The third LED unit LEU3 may include a third reflective layer 41 r and a fourth reflective layer 45 r together with the third light emitting stack 40 and the contact electrode 45P. The third reflective layer 41 r may be disposed at an opposite side of the contact electrode 45P. As shown in FIG. 4, the contact electrode 45P may form ohmic contact with the second conductivity type semiconductor layer 45 and the third reflective layer 41 r may be formed at one side of the first conductivity type semiconductor layer 41. The third reflective layer 41 r may form ohmic contact with the first conductivity type semiconductor layer 41, without being limited thereto. That is, the third reflective layer 41 r may form Schottky contact with the first conductivity type semiconductor layer 41 or may be insulated from the first conductivity type semiconductor layer 41.

The fourth reflective layer 45 r may be formed on the contact electrode 45P. The second bonding layer 63 may couple the fourth reflective layer 45 r to the contact electrode 35 p.

The third and fourth reflective layers 41 r, 45 r reduce light loss by reflecting light emitted from the third light emitting stack 40. In addition, the fourth reflective layer 45 r may reflect light emitted from the second light emitting stack 30.

According to this embodiment, light emitted from the first light emitting stack 20 may be reflected by the first reflective layer 21 r and the second reflective layer 31 r. Accordingly, it is possible to reduce light loss by preventing light from being discharged from the first light emitting stack 20 in an undesired direction using the first reflective layer 21 r and the second reflective layer 31 r.

Light emitted from the second light emitting stack 30 may be reflected by the second reflective layer 31 r and the fourth reflective layer 45 r. Accordingly, it is possible to reduce light loss by preventing light from being discharged from the second light emitting stack 30 in an undesired direction using the second reflective layer 31 r and the fourth reflective layer 45 r.

Light emitted from the third light emitting stack 40 may be reflected by the third reflective layer 41 r and the fourth reflective layer 45 r. Accordingly, it is possible to reduce light loss by preventing light from being discharged from the third light emitting stack 40 in an undesired direction using the third reflective layer 41 r and the fourth reflective layer 45 r.

The first to fourth reflective layers 21 r, 31 r, 41 r, 45 r may be metal reflective layers, without being limited thereto. For example, the first to fourth reflective layers 21 r, 31 r, 41 r, 45 r may be insulating reflective layers, such as distributed Bragg reflectors (DBR). For the DBRs, the first to fourth reflective layers may be formed as multi-wavelength reflectors adapted to reflect light in the overall wavelength band including blue, green and red wavelengths, in which the multi-wavelength reflectors may be narrow-band reflectors capable of selectively reflecting the corresponding wavelength bands depending on the location of each of the reflective layers. In this case, the first to fourth reflective layers 21 r, 31 r, 41 r, 45 r may be formed to different optical thicknesses or formed of different materials for high refractivity material layers and low refractivity material layers in order to reflect light in a desired wavelength band. For example, the first reflective layer 21 r may selectively reflect red light, the third reflective layer 41 r may selectively reflect blue light, and the second reflective layer 31 r and the fourth reflective layer 45 r may selectively reflect light in a relatively broad wavelength band, for example, in the overall wavelength band of the visible spectrum.

FIG. 16 is a schematic sectional view of a light emitting device 100 d according to one exemplary embodiment of the present disclosure.

Referring to FIG. 16, the light emitting device 100 d according to this embodiment is generally similar to the light emitting device 100 c described with reference to FIG. 15 except that the first to third light emitting stacks 20, 30, 40 and/or the contact electrodes 25 p, 35 p, 45 p are formed with roughness for light scattering. The roughness may be formed on the first conductivity type semiconductor layers 21, 31, 41 or the second conductivity type semiconductor layers 25, 35, 45 of the first to third light emitting stacks 20, 30, 40 and may be formed on the contact electrodes 25 p, 35 p, 45 p. The roughness may be formed by various methods such as deposition or etching techniques and may be formed regularly or irregularly. The roughness scatters light emitted from the light emitting stacks 20, 30, 40 and increases the quantity of light emitted from the light emitting stacks 20, 30, 40.

FIG. 17 is a schematic sectional view of a light emitting device 100 e according to one or more exemplary embodiments of the present disclosure.

Referring to FIG. 17, the light emitting device 100 e according to this embodiment is generally similar to the light emitting device 100 c described with reference to FIG. 15 and further includes ohmic electrodes 21 m, 31 m, 41 m.

The first ohmic electrode 21 m may be disposed between the first light emitting stack 20 and the first reflective layer 21 r and forms ohmic contact with the first conductivity type semiconductor layer 21 of the first light emitting stack 20. The second ohmic electrode 31 m may be disposed between the second light emitting stack 30 and the second reflective layer 31 r and forms ohmic contact with the first conductivity type semiconductor layer 31 of the second light emitting stack 30. The third ohmic electrode 41 m may be disposed between the third light emitting stack 40 and the third reflective layer 41 r and forms ohmic contact with the first conductivity type semiconductor layer 41 of the third light emitting stack 40.

The first, second and third ohmic electrodes 21 m, 31 m, 41 m serve to achieve uniform distribution of electric current in the first to third light emitting stacks 20, 30, 40.

FIG. 18 is a schematic perspective view of a light emitting device 100 f according to one exemplary embodiment of the present disclosure.

Referring to FIG. 18, the light emitting device 100 f according to this embodiment is generally similar to the light emitting device 100 b described with reference to FIG. 9 except that the common electrode 50 e is commonly connected to the first LED unit LEU1 and the third LED unit LEU3 through through-holes 11 h formed through the substrates 11 a, 11 b.

The through-holes 11 h may be formed through the substrates 11 a, 11 b and may be formed of a conductive material, for example, a metal or a semiconductor material. The common electrode 50 e may be connected to the first LED unit LEU1 and the third LED unit LEU3 through the through-holes 11 h instead of being connected thereto at the sides thereof. Here, the common electrode 50 e may be connected to the second LED unit LEU2 at one side of the second LED unit LEU2.

Although the common electrode 50 e is illustrated as being electrically connected to the first and third LED units LEU1, LEU3 through the through-holes 11 h formed through the substrates 11 a, 11 b in this embodiment, the first electrode 20 e and the third electrode 40 e may be electrically connected to the first LED unit LEU1 and the second LED unit LEU2 through the through-holes 11 h, respectively.

FIG. 19 is a schematic perspective view of a light emitting device module 300 according to one exemplary embodiment of the present disclosure.

Referring to FIG. 19, the light emitting device module 300 according to this embodiment is generally similar to the light emitting device module described with reference to FIG. 10 or FIG. 11 and further includes a carrier substrate 200.

The carrier substrate 200 may include connectors 220, 230, 240, 250 connected to the electrodes 20 e, 30 e, 40 e, 50 e of the light emitting devices 100 b. The carrier substrate 200 may be formed of the same material as the substrate for growth of semiconductor layers, such as a sapphire substrate or a GaAs substrate, without being limited thereto. For example, the carrier substrate 200 may be formed of an inorganic material, such as glass, or an organic material, such as an epoxy.

In this embodiment, the connectors 220, 230, 240, 250 may be formed by bonding the carrier substrate 200 to the light emitting devices 100 b, followed by forming through-holes and filling the through-holes with a conductive material. Alternatively, the connectors 220, 230, 240, 250 may be previously formed on the carrier substrate 200, which in turn may be attached to the light emitting devices 100 b.

In this embodiment, the connectors 220, 230, 240, 250 may be arranged at larger intervals than the electrodes 20 e, 30 e, 40 e, 50 e, whereby the carrier substrate 200 can act as an interposer.

FIG. 20 is a schematic perspective view of an LED display apparatus 2000 according to one exemplary embodiment of the present disclosure.

Referring to FIG. 20, the LED display apparatus 2000 according to this embodiment includes a display substrate 101 and multiple light emitting device modules 300.

The light emitting device module 300 is the same as the light emitting device module described with reference to FIG. 19 and detailed description thereof will be omitted to avoid repetition.

The multiple light emitting device modules 300 may be disposed on the display substrate 101, thereby realizing the LED display apparatus. Furthermore, a large LED display apparatus 2000 may be realized by arranging multiple circuit boards 101 having the light emitting device modules 300 arranged thereon.

According to this embodiment, the light emitting devices 100 b may be mounted on the display substrate 101 using the carrier substrate 200, thereby facilitating the mounting process.

Although some exemplary embodiments and implementations have been described herein, other exemplary embodiments and modifications will be apparent from the above description. Therefore, it should be understood that the present disclosure is not limited to the above embodiments and should be interpreted according to the following appended claims and equivalents thereto. 

What is claimed is:
 1. A display apparatus comprising: a display substrate; and light emitting devices arranged on an upper surface of the display substrate, one or more light emitting devices comprising: a first LED unit comprising a first light emitting stack; a second LED unit comprising a second light emitting stack; and a third LED unit comprising a third light emitting stack, wherein the second LED unit is disposed between the first LED unit and the third LED unit, each of the first, the second and the third light emitting stacks comprises a first conductivity type semiconductor layer and a second conductivity type semiconductor layer, and the first conductivity type semiconductor layer and the second conductivity type semiconductor layer in each of the first, the second and the third light emitting stacks are disposed perpendicular to the upper surface of the display substrate and stacked in a horizontal direction with respect to the upper surface of the display substrate.
 2. The display apparatus according to claim 1, wherein each of the first to third light emitting stacks further comprises an active layer interposed between the first conductivity type semiconductor layer and the second conductivity type semiconductor layer.
 3. The display apparatus according to claim 1, wherein one of the first, the second and the third LED units emits red light, another LED unit emits green light, and the remaining LED unit emits blue light.
 4. The display apparatus according to claim 3, wherein the second LED unit emits red light.
 5. The display apparatus according to claim 1, wherein said one or more light emitting devices further comprise a substrate disposed at one side of the third LED unit.
 6. The display apparatus according to claim 5, wherein said one or more light emitting devices further comprise a substrate disposed at one side of the first LED unit.
 7. The display apparatus according to claim 1, wherein the light emitting devices are spaced apart from one another by a black material.
 8. The display apparatus according to claim 1, comprising: multiple light emitting device modules arranged parallel to one another on the display substrate, each of the light emitting device modules comprising multiple light emitting devices coupled to one another in a direction in which the first conductivity type semiconductor layer and second conductivity type semiconductor layer are stacked.
 9. The display apparatus according to claim 8, wherein the light emitting devices in each of the light emitting device modules further comprise a substrate of a black material.
 10. The display apparatus according to claim 9, further comprising: a black material disposed in a region between the light emitting device modules.
 11. The display apparatus according to claim 1, wherein one or more light emitting devices further comprise: a first electrode electrically connected to the first LED unit, a second electrode electrically connected to the second LED unit, a third electrode electrically connected to the third LED unit, and a common electrode electrically connected to the first to third LED units.
 12. The display apparatus according to claim 11, wherein the first through the third LED electrodes and the common electrode are disposed between the at least one light emitting device and the display substrate.
 13. The display apparatus according to claim 12, further comprising: a carrier substrate disposed between the display substrate and the at least one light emitting device, the carrier substrate comprising connectors electrically connecting the first through the third electrodes and the common electrode to connection pads of the display substrate.
 14. A display apparatus comprising: a display substrate; and light emitting devices arranged on an upper surface of the display substrate, one or more the light emitting devices comprising: a first LED unit comprising a first light emitting stack; a second LED unit comprising a second light emitting stack; a third LED unit comprising a third light emitting stack; a first bonding layer coupling the first LED unit to the second LED unit; and a second bonding layer coupling the second LED unit to the third LED unit, wherein the first, the second and the third LED units are coupled side by side in a horizontal direction with respect to the upper surface of the display substrate.
 15. The display apparatus according to claim 14, wherein the second LED unit emits red light.
 16. A light emitting device comprising: a first LED unit comprising a first light emitting stack; a second LED unit comprising a second light emitting stack; a third LED unit comprising a third light emitting stack; a first bonding layer coupling the first LED unit to the second LED unit; a second bonding layer coupling the second LED unit to the third LED unit; a first electrode electrically connected to the first LED unit; a second electrode electrically connected to the second LED unit; a third electrode electrically connected to the third LED unit; and a common electrode electrically connected to the first to third LED units, wherein the second electrode is electrically connected to the second LED unit on one side surface of the second LED unit.
 17. The light emitting device according to claim 16, wherein the first electrode, the second electrode, the third electrode, and the common electrode are disposed on one side surface of the light emitting device; and wherein: the first LED unit further comprises a first contact electrode forming ohmic contact with the first light emitting stack; the second LED unit further comprises a second contact electrode forming ohmic contact with the second light emitting stack; the third LED unit further comprises a third contact electrode forming ohmic contact with the third light emitting stack; and at least one of the first to third light emitting stacks or at least one of the first to third contact electrodes has roughness.
 18. The light emitting device according to claim 16, further comprising: a first substrate coupled to the first LED unit; and a second substrate coupled to the second LED unit, wherein the first substrate and the second substrate comprise through-holes, one of the first electrode and the common electrode is electrically connected to the first LED unit through the through-hole of the first substrate, and one of the third electrode and the common electrode is electrically connected to the third LED unit through the through-hole of the second substrate.
 19. The light emitting device according to claim 16, further comprising: a substrate disposed at one side of the third LED unit, wherein a portion of the third electrode is disposed on one side surface of the substrate.
 20. The light emitting device according to claim 16, wherein: the first LED unit further comprises a first reflective layer disposed on the first light emitting stack; the second LED unit further comprises a second reflective layer disposed on the second light emitting stack; the third LED unit further comprises a third reflective layer and a fourth reflective layer disposed at opposite sides of the third light emitting stack; a first ohmic electrode interposed between the first light emitting stack and the first reflective layer; a second ohmic electrode interposed between the second light emitting stack and the second reflective layer; and a third ohmic electrode interposed between the third light emitting stack and the third reflective layer. 